Researchers in Australia raised new concerns about the Great Barrier Reef recently with a study that found that coral there are actually eating small bits of plastic that are floating in the water.

A study published Tuesday in the journal Marine Biology found that coral collected from the Great Barrier Reef and placed into plastic-contaminated water ate plastic at rates only slightly lower than their normal rate of feeding on marine plankton, Science Daily reported.

The reef is already threatened by climate change, poor water quality from land-based run-offs, coastal developments, and fishing, and as much as 88 percent of the open ocean's surface contains plastic debris, AFP said.

Microplastics are particles smaller than a fifth of an inch. They come from such sources as toys, bags, food containers, and utensils, and generally enter the sea from storm water run-off.

Twitter users expressed their concerns.

Hmmm. Coral eating micro-plastics in Australia's Great Barrier Reef. Can that be good??? http://t.co/78z8rnWiGI